646823 has 2 divisors, whose sum is σ = 646824. Its totient is φ = 646822.

The previous prime is 646781. The next prime is 646831. The reversal of 646823 is 328646.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646823 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323411 + 323412.

It is an arithmetic number, because the mean of its divisors is an integer number (323412).

2⁶⁴⁶⁸²³ is an apocalyptic number.

646823 is a deficient number, since it is larger than the sum of its proper divisors (1).

646823 is an equidigital number, since it uses as much as digits as its factorization.

646823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 29.

The square root of 646823 is about 804.2530696242. The cubic root of 646823 is about 86.4825496334.

The spelling of 646823 in words is "six hundred forty-six thousand, eight hundred twenty-three".